In the production of microelectronic chips, a wafer is first processed to form the microelectronic parts and circuits, and then diced into many individual dies. One or more dies are then packaged together for protection against the elements and in some cases to make the packages easier to handle and install. The package has an array of connections on one side and a plastic cover or a resin that is molded over the package on the other side. Sometimes other protective materials are used as alternatives.
The side opposite the electrical connections is typically a dull black color that is marked in white with a number to indicate the type of die inside and the manufacturer. The name of the manufacturer may be spelled out or indicated by the number. There may also be batch numbers or date references in various coded numbers and letters printed on the package. In a few cases, there is a symbol or graphic legend marked on the package. After these packages are mounted to a printed circuit board, the white markings are facing up away from the board and are legible in most cases by a shopper or service technician. When the package is covered with a heat sink or heat fins, then the product number may not be visible.